During her headline slot on Saturday night the US singer dedicated a performance of Part Of Me to the people of Manchester following the attack on a pop concert.
She said: "I think that we're all extremely brave and we're all in this together, aren't we?
"We will still dance, we will still sing, we will still make music.
"This next one goes out to Manchester and all the people who know what it means to love music and be a community because of it."
Asking her fans to hold hands with the person next to them, she added: "This is a part of us that they'll never take away from us. Rest in peace Manchester."
Radio 1 DJ Nick Grimshaw led the crowd in a minute's silence at the festival in Hull which took place amid a high level of security.
He said: "Like you guys, all of us at Radio 1 have been thinking about Manchester all week and we've been completely heartbroken."
Scottish singer Emeli Sande dedicated a rendition of Read All About It to those affected by the bombing that took place moments after a concert by US star Ariana Grande.
She said: "Make some noise for yourselves and bringing people together, something you should never be afraid to do.
"Use your voice to change the world."
Kasabian's guitarist Sergio Pizzorno spoke of his "heartbreak" at the attack in Manchester.
The musician, who has two sons, told the Press Association: "I'm so familiar with that place (the arena), I know that foyer, I know that building, it was so hard to get my head around an attack of that magnitude.
"Everything about it is so close to home and I've got boys myself.
"I'm just completely and utterly heartbroken."
During her set Swedish singer Zara Larsson told the crowd: "Music itself, it doesn't have a religion, it doesn't have a country, or an ethnicity, it's something that we do and it unites us all.
"I want this song to be dedicated to what happened in Manchester. It's about wanting to be a part of someone's symphony, someone's life. That to me is the most beautiful thing."
Dan Reynolds, frontman of Imagine Dragons, told the Press Association: "It's been a really sad, tragic week and felt across the world, especially in the music community.
"But the music industry is also standing up and saying no individual is going to stop music and put fear into the hearts of any of us. Music will continue."